The author of Luke writes: "Now it came about in those days that a decree went out from Caesar Augustus, that a census be taken of all the inhabited earth. This was the first census taken while Quirinius was governor of Syria. And all were proceeding to register for the census, everyone to his own city. And Joseph also went up from Galilee, out of the city of Nazareth, to Judea, to the city of David, which is called Bethlehem, because he was of the house and family of David, in order to register, along with Mary, who was engaged to him, and was pregnant" (Luke 2:1-5).
Why has it been said that if the Roman census described in the Gospel of Luke was actually carried out as described it would have caused chaos and unprecedented danger to the Roman Empire?
In Matthew, Mary and Joseph appear to live in Bethlehem and did not need to travel there prior to Jesus' birth. The author of Luke had to get Mary to Bethlehem to have her baby in order to have what he believed was prophetic fulfillment of Micah 5:1. For this he devised a census using as his basis an actual census that took place around the time when Jesus was born.
It is not plausible that the Romans conducted a census in the manner described by Luke. There would have been no reason for them to demand that the people being enumerated return to the towns of their ancestors rather than register in the towns in which they actually resided. There would have been no need to make a difficult situation worse. It was obviously unnecessary for people to have to travel to a place often hundreds of miles away which they probably had never seen before.
According to Luke, everyone residing in the Empire who was not in "his own city" had to leave his place of residence to go to register in his ancestral town. The use of the phrase "to his own town," as found in Luke, does not mean the city of one's birth or official permanent residence, for we see that, in Joseph's case these were not the reasons given for his going to Bethlehem. He went there because, Luke says, he was of Davidic descent. Luke writes that it was not one's own birthplace or official permanent residence that governed what was one's destination, but the earliest place of residence of one's most distant ancestors.
The alleged Roman demand presumes that the people all knew their ancestral origins and that their ancestors lived with the Empire. This census was sure to cause the disruption of normal family, social, and economic life.
What Luke describes has the makings of a chaotic situation of unprecedented magnitude. The people involved would have had to travel throughout the length and breath of the Roman Empire, clogging the roads and disrupting the smooth running of the imperial system in every province of the Empire. In the course of their journey, they would be traveling, for the most part, over extremely poor roads once they left the major Roman highways. Available services to travelers would be strained to the breaking point. Certainly in the eastern provinces, of which Judea was part, such a census would present a serious military danger, for the Parthians, then Rome's strongest antagonist in the area, would have had an excellent opportunity to attack. Roman troops on the march would find it extremely difficult to compete with the tremendous mass of civilians on their way to or from registration. It is hard to imagine the Romans so incompetent or unrealistic as to throw the entire Empire into such a chaotic state by carrying out the census described by the evangelist.
It is unusual that an event of this magnitude should go unnoticed. Yet no contemporary writer mentions this disruptive census or the turmoil it would have engendered. Indeed, if this census took place in Judea it is strange that Josephus never mentioned it in any of his writings. It is obvious that Luke introduced the tale to explain still another legendary tale, that is, how it came about that Joseph and Mary went to Bethlehem at this time.